I have microsoft outlook 2002 and i dont know the

You'll need to check the "Accounts" settings, most likely under "Tools" from the menu bar. This is where the EMail accounts are setup up for your Internet Service Provider. Make sure you don't have 2 or more accounts with the same server name, user name, and passwords.
This link explains why:
http://support.microsoft.com/kb/281791

Check with your Internet Service Provider if you forgot your email name and/or password to have them reset it. Then make sure to put the correct info into your Outlook "Accounts" to get your email.